Today’s round-up ranges from late-breaking news of iOS apps that crash on launch to long-standing problems with email.

Outbreak of iOS app crashes

If you find that a number of your recently updated iOS apps are crashing on launch, you are not alone. Such apps include Instapaper, GoodReader, Angry Birds Space Free and dozens more. As first reported by Marco Arment (and covered here at Macworld), the cause appears to be corrupted copies of apps being pushed from Apple’s servers, starting around July 3. The apps, as submitted by the developer to Apple, were not corrupt. The problem was introduced by Apple somewhere between the submission and when the app arrives on your iOS device. It’s probably related to FairPlay, Apple’s DRM software.

The only sure fix is to wait for Apple to replace the bad copies of the apps with good ones. (And, at this point, you shouldn't have to wait long or at all. Apple replied to Macworld’s request for additional information and stated that the problem had been resolved and wasn’t expected to occur again.) You then delete the corrupted app and install a fresh copy. If this means you would wind up losing saved data, such as game high scores, you can save it using a technique detailed here at Macworld by Chris Breen. The folks who make GoodReader offer a different solution for saving data stored with their app. [Note to Apple: You should provide an iOS feature that makes it easier to preserve data in these situations; but that’s a topic for another day.]

During this same time frame, my copy of Angry Birds Seasons HD started crashing on launch. This may have been a coincidence, as the symptom was slightly different. Rather than crashing immediately upon launch, the crash happened just after the app finished “loading.” In experimenting with various potential fixes, I found that, if I turned off all network access (Wi-Fi and LTE), the app would launch successfully. I could then re-able network access without the crash returning. This may not work for you, but it’s worth a try.

Disappearing email

The problem: Email messages disappear from the Mail app on your iOS device, even though they are still accessible from your Mac. What’s going on?

POP vs. IMAP. This is such a long-standing cause that I hesitated to mention it. But I suspect it’s still a source of problems for some users. Let’s assume you are using an app (not a web browser) for email on your Mac and have an email account set up as POP—with it set to delete messages from the server after they are downloaded. If you have the same account set up as IMAP on your iOS device, messages may disappear from your iOS device after checking mail on your Mac. This is because IMAP accounts typically only show messages that are still on the server. The simplest solution is to set up the email account as IMAP on both devices.

A similar vanishing act can result, even with an IMAP account on your Mac, if you move email messages from the Inbox to a separate folder—if your Mac’s email app is set to delete messages from the server when they are moved from the Inbox.

“No Limit” Exchange setting. If email is disappearing from a Microsoft Exchange account on your iOS device, go to Settings -> Mail, Contacts, Calendars and select the Exchange listing. From here, scroll down to the “Days to Sync” option. To make sure that no messages ever disappear, choose “No Limit” from the available durations. With any other choice, messages will be deleted after the specified time (e.g., 1 Day).

“Days to Sync” is only present for Exchange accounts. However, even if you have this option, you may find that the “No Limit” choice is not available. Apparently, some ISPs disable the feature, probably to prevent an overload of messages being delivered to your iOS device (you could have thousands of messages on the server). As covered in an Apple Support Communities thread, this removal was happening with at least some GoDaddy Exchange accounts. Assuming you are certain you want the “No Limit” setting, postings in the thread describe work-arounds. As one example, you can temporarily disable syncing, which should bring the “No Limit” option back. After you select it, re-enable syncing. The option should remain in effect even though it is no longer listed in “Days to Sync.”

Gmail not working

The problem: You cannot send or receive email from your Gmail account in Mail on your Mac. Each time you try, Mail asks for your password, claiming that the one already entered is incorrect. You are certain that the entered password is the right one. What’s going on?

Based on my web search, this is a fairly common, although intermittent, problem. And it recently plagued a friend of mine, who asked me for help. I tried several potential suggested fixes, including various manipulations of the Gmail account settings in Mail. Nothing worked. What finally did the trick was launching Keychain Access and deleting all the Gmail items. After that, we returned to Mail and tried again to receive messages. Success!

To comment on this article and other Macworld content, visit our Facebook page or our Twitter feed.